Various configurations have heretofore been proposed to enhance efficiency of transducers of this type during recording and enhance the resolution of transitions during reading. U.S. Pat. Nos. 3,700,827 and 4,016,601 constitute the most pertinent prior art presently known to applicants relating to their transducer configuration.
U.S. Pat. No. 3,700,827 discloses a thin film magnetic head with a yoke structure that narrows from a back region to a pole tip region. A separate magnetic core interconnects the yoke pieces at the back region. A wire coil encircles the magnetic core for activating the pole pieces during recording and transmitting electrical pulses activated in the coil during reading of magnetic transitions from a magnetic recording medium.
U.S. Pat. No. 4,016,601 discloses an integrated magnetic head assembly wherein the pole pieces have a reduced width in the pole tip region and a flat conductor winding coil has a branch inserted between the pole piece layers. The reduction in width in the pole tip region is achieved by etch removal of concave portions of the substrate and pole pieces, such that the distance between the end of the pole tip and the wide portion of the yoke structure is greater than the thickness of one of the magnetic layers plus the magnetic gap.
This prior art does not suggest applicants' improved thin film inductive transducer wherein resolution is maximized during reading by providing a pole tip region of preselected constant relatively narrow width comprising two thin magnetic layers that extend in a direction normal to the magnetic medium. The effects of spurious signals from adjacent tracks on the medium are minimized by having the pole tip region extend a distance at least 5/d, where d is the recording density; however, to maximize transducer efficiency, said distance should not be increased significantly above 5/d. Saturation of the yoke structure with applied current is opposed and efficiency of the transducer is enhanced during recording by increasing the cross-sectional area of the yoke structure in the back region by progressively increasing its width rearward of the pole tip region and concurrently increasing the thickness of said magnetic layers at least about 60%.